1. Field
Embodiments of the present disclosure relate to an in-wheel motor system, and more particularly, to an in-wheel motor system capable of maximizing a spatial efficiency by improving a mounting structure thereof.
2. Description of the Related Art
In general, an in-wheel motor is a technology used for an electric vehicle using electricity as a driving source, and differently from a gasoline vehicle or a diesel vehicle in which a wheel is rotated by a power sequentially transmitted through an engine, a transmission, and a driving shaft, is an apparatus enabling a power to be delivered to a wheel through a motor disposed inside a rim of the wheel.
By using the in-wheel motor, a power transmission apparatus, such as an engine, a transmission, or a differential gear, is omitted, the weight of the vehicle is reduced and a wheel is independently controlled, while the vehicle running performance is improved and the energy loss in a power transmission process is reduced.
FIG. 1 is a perspective view illustrating a state of having a conventional in-wheel motor system installed at a wheel, and FIG. 2 is an assembled cross-sectional view of FIG. 1.
Referring to FIGS. 1 and 2, an in-wheel motor system is installed at a wheel 10 from an inside a vehicle to an outside the vehicle. In detail, the in-wheel motor system is provided with an axle 20 installed at the center of a wheel 10 and rotating together with the wheel 10, a decelerator 30 transmitting a rotational force of an in-wheel motor 40 at a reduced speed, the in-wheel motor 40 connected to the decelerator 30, and a disc brake 60 to generate a braking force by pressing a disc 50 provided between the wheel 10 and the axle 20.
The in-wheel motor system needs to have the decelerator 30 to increase a torque of the in-wheel motor 40, and in addition, a brake system, that is, the disc 50 and the disc brake 60, needs to be installed inside the wheel 10. Accordingly, if the in-wheel motor system as such is coupled on the wheel 10, the spatial efficiency is lowered and an unsprung mass is increased, while degrading a vehicle running performance.
In particular, if the in-wheel motor system is mounted on the wheel 10, the disc 50, the disc brake 60, and the decelerator 30 are disposed inside the wheel 10. In this case, due to the spatial limitation of the inside the wheel 10, the in-wheel motor 40 protrudes toward the outer side of the wheel 10, that is, toward an interior of the vehicle, so that the in-wheel motor 40 may be broken by impact with an external object.